* {
    margin: 0;
    padding: 0;
}

body {
    background-color: rgb(51, 73, 94);
    perspective:1500px;
    
}
/* 导航栏开始 */
nav {
    width: 960px;
    height: 50px;
    background-color: rgb(51, 73, 94);
    position: relative;
    border-radius: 10px;
    box-shadow: 0 2px 3px rgba(0, 0, 0, 0.1);
    margin-right: 2px;
    margin-left: 250px;
}
nav a {
    position: relative;
    display: block;
    float: left;
    font-size: 15px;
    line-height: 50px;
    width: 240px;
    height: 50px;
    color: #fff;
    text-transform: uppercase;
    text-decoration: none;
    text-align: center;
    z-index: 10;
    transition: all 0.3s;
}

nav a:nth-child(1) {
    width: 240px;
}

nav a:nth-child(2) {
    width: 240px;
}

nav a:nth-child(3) {
    width: 240px;
}

nav a:nth-child(4) {
    width: 240px;
}

nav .animation {
    position: absolute;
    height: 100%;
    background-color: #f97f51;
    z-index: 9;
    border-radius: 10px;
    transition: all 0.3s;
}
nav a:hover{
    transform: scale(1.5,1.5);
}

.start-home,
nav a:nth-child(1):hover~.animation {
    width: 240px;
    left: 0;
}

nav a:nth-child(2):hover~.animation {
    width: 240px;
    left: 240px;
}

nav a:nth-child(3):hover~.animation {
    width: 240px;
    left: 480px;
}

nav a:nth-child(4):hover~.animation {
    width: 240px;
    left: 720px;
}
/* 导航栏结束 */

.lyrics-bg{
    width: 245px;
    height: 1242px;
    top: 50px;
    display: block;
    transition: all 0.5s;
}
 .lyrics-bg:hover{
    background: rgb(119,118,72);
    animation: jianbian 1s linear 0 0deg;
} 
.lyrics-bg video{
           width: 105px;
           height: 40px;
           position: absolute;
           background-color: rgb(51, 73, 94);
           z-index: -999;
           overflow: hidden;
           object-fit: cover;
           position: absolute;
           left: 54px;
           top: 0;
}
@keyframes jianbian{
    0%{
        background:rgb(51, 73, 94) ;
    }
    100%{
        background:rgb(119,118,72) ;
    }
}
.lyrics{
   margin-left: -9999px;
   overflow: hidden;
   color: rgb(253, 253, 196);
}
.lyrics:hover{
    margin-left: 0;
    
}
/* 播放，暂停按钮开始 */
.btn{
    position: absolute;
    width: 245px;
    height: 50px;
    margin-top: -1291px;
}
.btn button{
    margin: 5px 35px;
    position:relative;
    display: block;
    float: left;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    color: white;
    background: #3c88dd;
    transition: 0.5s;
}
.btn button:hover{
    background-color: #f97f51;
} 
 /* 播放，暂停按钮结束 */
 /* 集体照开始 */
 .group{
     width: 963px;
     height: 500px;
     position:absolute;
     left: 252px;
     background-color: #fff;
     top: 50px;
      overflow: hidden; 
      border-radius: 12px;
     
 }
 .group img{
     width: 100%;
     height: 100%;
     position: absolute;
     margin: auto;
     float: left;
     border-radius: 12px;
     animation: lunbo 30s linear infinite ;
 } 
.group img:nth-child(1){
    left: 0;
}
.group img:nth-child(2){
    left: 100%;
    
 }
.group img:nth-child(3){
   left: 200%;
    
 }
.group img:nth-child(4){
   left: 300%;
    
 }
.group img:nth-child(5){
    left: 400%;
 }
 @keyframes lunbo{
     0%,18%{
         margin-left: 0;
     }
     20%,38%{
         margin-left: -963px;
     }
     40%,58%{
         margin-left: -1926px;
     }
     60%,78%{
         margin-left: -2889px;
     }
     80%,100%{
         margin-left: -3852px;
     }
 }
 /* 集体照结束 */
 /* rotate开始 */
 section{
     width: 350px;
     height: 250px;
     position: absolute;
     left: 520px;
     top: 800px;
     transform-style: preserve-3d;
     animation: rotate 10s linear infinite;
 }
 section img{
     width: 100%;
     height: 100%;
     position: absolute;
 }
  section img:nth-child(1){
     transform: translateZ(380px);

 }
 section img:nth-child(2){
    transform:rotateY(60deg) translateZ(380px);

}
section img:nth-child(3){
    transform:rotateY(120deg) translateZ(380px);

}
section img:nth-child(4){
    transform:rotateY(180deg) translateZ(380px);

}
section img:nth-child(5){
    transform:rotateY(240deg) translateZ(380px);

}
section img:nth-child(6){
    transform:rotateY(300deg) translateZ(380px);

}
@keyframes rotate{
    0%{
        transform: rotateY(0);
    }
    100%{
        transform: rotateY(360deg);
    }
}
section:hover{
    animation-play-state: paused;
} 
 /* rotate结束 */
 .btn1{
     position: absolute;
     bottom: 0;
     left: 245px;
 }
 .btn2{
     position: absolute;
     bottom: 0px;
     right: 0;
 }